1. TROPICAL CYCLONE 18P (JOSIE) WARNING NR 011
02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
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WARNING POSITION:
030000Z --- NEAR 21.7S 179.2E
MOVEMENT PAST SIX HOURS - 120 DEGREES AT 04 KTS
POSITION ACCURATE TO WITHIN 030 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
215 NM SOUTHEAST QUADRANT
095 NM SOUTHWEST QUADRANT
115 NM NORTHWEST QUADRANT
REPEAT POSIT: 21.7S 179.2E
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FORECASTS:
12 HRS, VALID AT:
031200Z --- 22.7S 179.7W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING SUBTROPICAL
RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT
260 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 130 DEG/ 07 KTS
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24 HRS, VALID AT:
040000Z --- 23.6S 178.5W
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING SUBTROPICAL
RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
335 NM SOUTHEAST QUADRANT
100 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 125 DEG/ 08 KTS
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36 HRS, VALID AT:
041200Z --- 24.5S 177.0W
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING SUBTROPICAL
RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
435 NM SOUTHEAST QUADRANT
155 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 130 DEG/ 12 KTS
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EXTENDED OUTLOOK:
48 HRS, VALID AT:
050000Z --- 26.0S 174.9W
MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
WIND RADII VALID OVER OPEN WATER ONLY
SUBTROPICAL
RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
415 NM SOUTHEAST QUADRANT
195 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
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REMARKS:
030300Z POSITION NEAR 22.0S 179.5E.
TROPICAL CYCLONE 18P (JOSIE), LOCATED APPROXIMATELY 221 NM SOUTH-
SOUTHEAST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 04
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED MUTLI-SPECTRAL
(MSI) SATELLITE IMAGERY SHOWS AN EXPOSED LOW LEVEL CIRCULATION
CENTER (LLCC) WITH DEEP CONVECTION SHEARED 80 NM TO THE SOUTHEAST.
THE INITIAL POSITION IS BASED ON THE EXPOSED LOW LEVEL FEATURE IN
THE MSI LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 40 KNOTS
IS BASED ON EXTRAPOLATION FROM A 022129Z METOP-A ASCAT PASS THAT
SHOWED 40 KNOT WIND BARBS IN THE SOUTHEAST QUADRAT WHICH IS SLIGHTLY
ABOVE MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM
T2.0 TO T2.5 FROM KNES AND PGTW RESPECTIVELY. UPPER LEVEL ANALYSIS
SHOWS THE SYSTEM HAS A POLEWARD OUTFLOW CHANNEL. ENVIRONMENTAL
ANALYSIS SHOWS THAT 17P IS IN AN AREA OF HIGH (30 TO 40 KNOTS)
VERTICAL WIND SHEAR AND IS TRACKING THROUGH AN AREA OF WARM (28
CELSIUS) SEA SURFACE TEMPERATURES. THE HIGH VERTICAL WIND SHEAR IS
CAUSING THE CONVECTION TO DISPLACE TO THE SOUTHEAST. TC 18P WILL
CONTINUE TO TRACK TO THE SOUTHEAST WHERE IT WILL ENCOUNTER COOLER
SEA SURFACE TEMPERATURES AND PERSISTENT UNFAVORABLE SHEAR. THE
COMBINATION OF THESE FACTORS WILL CAUSE 18P TO BEGIN TO TRANSITION
INTO A SUBTROPICAL SYSTEM BY TAU 12 AND BECOME COMPLETELY
SUBTROPICAL BY TAU 48. AVAILABLE DYNAMIC MODEL GUIDANCE IS IN
GENERALLY GOOD AGREEMENT THAT THE SYSTEM WILL TRACK TO THE
SOUTHEAST FOR THE DURATION OF THE FORECAST PERIOD. DUE TO THE GOOD
AGREEMENT AMONG THE MODELS, THERE IS OVERALL HIGH CONFIDENCE IN THE
JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030000Z IS
20 FEET. NEXT WARNINGS AT 030900Z, 031500Z, 032100Z AND 040300Z.
REFER TO TROPICAL CYCLONE 17P (IRIS) WARNINGS (WTPS32 PGTW)
FOR SIX-HOURLY UPDATES.
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